Process for the manufacture of nitro-celluloses



Patented July 12, 1938 I I UNITED STATES P TENToFFIcs PROCESS FOR THE MANUFACTURE OF NITRO-CELLULOSES August Noll, Mannheim, Germany, assignor of one-half to Zellstofifabrik Waldhof, Mannheim-Waldhof, Germany, a German company No Drawing. Application May 21, 1936, Serial No. 81,016. In Germany June 11, 1935 3 Claims. (Cl. 260-145) This invention relates to a process for the cosity can only be reduced to the required extent manufacture of nitro-celluloses from chemical by subsequent treatment in an autoclave.

wood pulp. The process and the particular advantages In the nitration of cellulose use has hitherto arising therefrom will hereinafter be illustrated 5 been made of nitrating acids, consisting of sulwith the aid of the following examples: 5

phuric acid, nitric acid and water, in varying Example I proportions.

It has now been ascertained that substantial 5 of a bleached pi o d ce lu ose wit a advantages are obtained by using a nitrating acid resin Content of We t d fo 30 mincontaining in an amount corresponding su t utes at a temperature of 30 C. with 95 kgs. of an 10 tially to about one fifth of the weight of the wood acid mixture Consisting Of 60% H2804, 25% I-INO3 pulp chlorine, such as can be obtained for ex- After the usual Washing and ample by adding small quantities of hydrochloric ripening, there was obtained a collodion cotton acid to a normal nitrating acid mixture containing of nitrogen having a distinct yel- 15 In this manner the advantage is obtained in low tinge, and a viscosity of 203 taking acetone 15 t fir t place that the product obtained is f a as unity (measured in a 2% acetone solution). lighter color, which is particularly important in When the treatment was Carried-.0111? in the t nitration of less pure raw materia1s Moresame manner but with the addition of 3 litres of over the process of the present invention enables hydrochloric a'Cid p cifi ravity 1.19) to the the viscosity of the solutions made from the reabove-Specified quantity of nitrating cid, there 20 sulting nitrocelluloses to be varied within certain Was Obtained. a collodion Cotton Containing limits, in imple manhen of nitrogen and having a relative viscosity of 4'7 t is known t t wood pulps th th usual taking acetone as unity. This collodion cotton resin content, of for example 0.8-1%, when niw s of a pure white color w ut t e s i htest trated with the aid of the hitherto normal nitrattinge f y and Completely qual to a 25 ing acids consisting of nitric acid, sulphuric acid COttOn made, p O d res nized celand water, furnish products having amore or less 1111058 as regards 0010 It could thus also be pronounced tinge of yellow, and that even when made into pr of a Cl White color.

these products are made into other products, such Example H as for example lacquers, plastic masses (cellu- 30 1 1 3 and t k Such products are t 5 kgs. of cotton linters were nitrated for 30 pletely white. Some grades of cotton that are not minutes at with 95 of nitrating acid a pure white also behave in similar fashion. p ed of H2804, 25% s and 5% However, when white cotton is used as the origin- After Washing and ripening which was ating material colorless products can be obtained. carried out in the usual manner, collodion 35 It is true that lighter products have been obtained ton was obtained which contained 12.1% nitro en by removing the resin from the raw cellulose and a relative Viscosity a 2% acetone prior to nitration, but apart from the fact that Solution) 294, taking acetone as ty. the effect thus achieved was often still incom- By Operating in the Same a but adding 40 plete, the additional cost of the resin extraction 3 litres of hydrochimic acid p fic gravity 40 renders the process commercially impracticable. 1.19) to the above-spe fi q y of nitrat- In carrying out the invention, te t ad h v ing acid, there was obtained a collodion cotton shown that the viscosity of the solutions made w chcontaincd 10.9% of nitrogen and which from the resulting nitrocellulose falls as the prohad a relative viscosity of 90, takin acet as portion of chlorine contained in the nitrating unity. 5

acid rises, so that it is possible to regulate the I claim: viscosity of the solutions to be made from the s 1. Aprocess for manufacturing nitro-celluloses,

nitrocellulose in simple manner within certain which process comprises nitrating cellulose raw limits. In particular it is easily possible in acals fo about 30 minutes at about 30 C.

cordance with the invention to make collodion with a nitrating acid Conta approximately 50 cottons direct, these being directly utilizable as furic a d, 243% n tric acid, and 3.7% lacquer cottons owing to the low viscosity of their hydrochloric acid. solutions, whereas a collodion cotton furnishing 2. Aprocess for manufacturing nitro-celluloses, highly viscous solutions is obtained without the which process compr ni rating cellulose raw addition of the hydrochloric acid, and the vlsmaterials for about 30 minutes at about 30 C. 55

with a nitrating acid containing approximately with about 20 times its weight quantity of a ni- 57.8% sulfuric acid, 24.3% nitric acid, 3.7% hytrating acid containing approximately 57.8% suldroch'loric acid, and 14.2% water. furic acid, 24.3% nitric acid and 3.7 hydro- 3. A process for manufacturing nitro-celluloses, chloric acid. 5 which process comprises nitrating cellulose raw AUGUST NOLL. 5

materials for about 30 minutes at about 30 0., 

